A method for repairing road surface hidden diseases by polymer loading and grouting

Abstract

This invention discloses a method for the coordinated control and repair of hidden pavement defects using polymer loading grouting, comprising: obtaining defect parameters and pavement structure parameters through non-destructive testing; establishing a fluid-structure interaction model based on these parameters, determining the critical loading pressure, and determining the lower limit of preloading by combining a limiting expansion test; calculating the initial preloading value and limiting the target pressure to obtain the verification preloading pressure after step preloading and displacement monitoring; estimating the expected injection volume; grouting under the constraint of the verification preloading pressure, using pavement displacement and its rate of change as the control target, coordinating the grouting flow rate and external constraint loading pressure, and performing anomaly detection and correction based on the back pressure of the loading plate, stopping grouting after reaching the stopping condition; finally, performing pressure-holding curing, graded unloading, rebound monitoring, and acceptance. This invention can effectively suppress bulging caused by grouting, improve the filling density of the defect area, and enhance the structural durability after repair.

Description

Technical Field

[0001] This invention belongs to the field of road engineering and underground hidden defects repair technology, and particularly relates to a method for polymer loading grouting synergistic control repair of hidden road surface defects. Background Technology

[0002] Hidden road surface defects (such as cracks, voids, and loosening) can lead to a decrease in the load-bearing capacity of the road structure, as well as cracking and subsidence. Polyurethane polymer grouting repair technology, with its advantages of speed, durability, economy, and environmental friendliness, has been widely used in the field of road defect repair. Currently, the polymer materials used in engineering are mainly divided into two categories: intumescent and penetrating. Penetrating polymers have excellent penetration and filling performance and stable repair effects, but the material cost is high, the cost is expensive, and the curing time is 1-3 days, limiting their economic viability in large-scale maintenance projects. Intumescent polymers have relatively low material costs and a relatively low cost, offering significant economic advantages and good repair effects. However, the expansion force generated during the curing process may cause the road surface to lift, bulge, and cause uneven deformation. Some projects use external loads to constrain the lifting, but there is usually a lack of calculable methods to determine the critical loading pressure, as well as a lack of dynamic matching mechanisms with grouting parameters, making it difficult to balance lifting control and filling uniformity. Summary of the Invention

[0003] To address the aforementioned technical problems, this invention proposes a method for the coordinated control and repair of hidden road surface defects using polymer loading grouting, thereby resolving the issues present in the prior art.

[0004] To achieve the above objectives, the present invention provides a method for the coordinated control and repair of hidden road surface defects by polymer loading grouting, comprising: Non-destructive testing is used to obtain the type of pavement defects, geometric parameters of defects, and pavement layer structure parameters of the road surface to be repaired. A fluid-structure interaction model is constructed based on the geometric parameters of the disease and the layered structure parameters of the pavement; the critical loading pressure is determined based on the fluid-structure interaction model; and the lower limit of preloading is determined by combining the slurry equivalent expansion pressure test. The initial preload value is calculated based on the geometric parameters of the defect; the initial preload value is limited between the lower limit of the preload and the critical loading pressure to obtain the target preload pressure; based on the target preload pressure, the preload pressure is checked by step preload and monitoring of road surface displacement to obtain the checked preload pressure; The estimated injection volume is estimated based on the equivalent volume of the defect, the slurry expansion ratio, and the volume margin coefficient. Polymer grouting is performed under the preloaded pressure constraint after verification. The initial grouting flow rate is set according to the expected injection volume. The grouting flow rate and the external constraint loading pressure are adjusted in coordination with the road displacement and the corresponding rate of change as the control target. Anomalies are identified and corrected based on the back pressure of the loading plate. Injection is stopped when the preset conditions are met. After stopping the injection, perform pressure maintenance, graded unloading and rebound monitoring in sequence, and complete the acceptance based on the condition after unloading.

[0005] Optionally, the non-destructive testing includes using three-dimensional ground-penetrating radar and a falling-weight deflectometer, combined with drilling or core sampling to verify the geometric parameters of the defect.

[0006] Optionally, the process of determining the critical loading pressure based on the fluid-structure interaction model includes: using the fluid-structure interaction model, calculating the displacement constraint pressure corresponding to when the road surface displacement reaches the allowable uplift threshold, and the strength constraint pressure corresponding to when the equivalent stress of the key parts of the road surface reaches the allowable stress threshold, and taking the smaller value of the two as the critical loading pressure.

[0007] Optionally, the lower limit of preloading is equal to the equivalent expansion pressure of the slurry measured by a limited expansion or constrained expansion test multiplied by a safety factor of 1.1 to 1.5.

[0008] Optionally, the process of verification through stepped preloading and monitoring road surface displacement includes: External constraint loading pressure is applied at each loading increment of 0.1 to 0.2 MPa or 0.1 to 0.25 times the preload target pressure, and maintained for 0.5 to 2 minutes after each loading increment; when the monitored road surface displacement reaches the warning displacement threshold or its rate of change exceeds the displacement growth rate threshold, the pressure increase is stopped and the current stable pressure is used as the verified preload pressure.

[0009] Optionally, the process of estimating the expected injection volume based on the equivalent volume of the defect, the slurry expansion ratio, and the volume margin coefficient includes: The expected injection volume is equal to the equivalent volume of the disease divided by the slurry expansion factor, and then multiplied by a volume margin coefficient of 1.0 to 1.3; wherein, the equivalent volume of the disease is determined according to the disease type based on the planar dimensions and thickness, crack dimensions or loose zone dimensions and porosity.

[0010] Optionally, the process of coordinating the grouting flow rate and external constraint loading pressure with road surface displacement and the corresponding rate of change as the control target, and performing anomaly detection and correction based on the back pressure of the loading plate, includes: Set the following thresholds: early warning displacement threshold, displacement change rate threshold, jacking sensitive displacement threshold, jacking sensitive change rate threshold, low back pressure threshold, high back pressure threshold, back pressure sudden change threshold, and back pressure invalid threshold; wherein, the jacking sensitive displacement threshold is less than the early warning displacement threshold, and the jacking sensitive change rate threshold is less than the displacement change rate threshold; When the back pressure of the loading plate is lower than the low value of the back pressure threshold, grouting is paused and the contact state of the loading plate is checked. Based on the check result, the external constraint loading pressure is increased within the range of the preload lower limit and the critical loading pressure. When the back pressure of the loading plate is higher than the high value of the back pressure threshold or the back pressure increment exceeds the back pressure sudden change threshold, reduce the grouting flow rate and switch to intermittent grouting or observation and maintenance. When the road surface displacement reaches the warning displacement threshold or the displacement change rate reaches the displacement change rate threshold, the grouting flow rate is reduced and the grouting is monitored for volume reduction. If the displacement change rate continues to exceed the displacement change rate threshold during the volume reduction monitoring period, grouting is stopped and the monitoring is switched to observation and maintenance. When the road surface displacement reaches the lifting sensitive displacement threshold or the displacement change rate reaches the lifting sensitive change rate threshold, and the back pressure of the loading plate is lower than the back pressure ineffective threshold, the grouting flow rate is reduced and the displacement change rate control target is tightened. At the same time, the external constraint loading pressure is increased without exceeding the critical loading pressure.

[0011] Optionally, the process of setting the initial grouting flow rate also includes setting differentiated rate limiting coefficients for different types of defects and adapting them to different grouting processes, including: When the disease type is crack, a rate limiting coefficient of 0.5 to 0.8 is used, and a segmented small flow injection process is adopted; When the disease type is voiding, a rate limiting coefficient of 0.7 to 1.0 is used, and a multi-point zonal injection or hole position rotation injection process is adopted. When the disease type is loose, a rate limiting coefficient of 0.6 to 0.8 is used, and a process of alternating hole positions and intermittent injection is adopted.

[0012] Optionally, the duration of the pressure-holding curing is not less than 1.0 to 2.0 times the initial setting time of the slurry; during the staged unloading process, each stage of unloading is maintained for 2 to 10 minutes. If the detected rebound amount exceeds the rebound threshold, the unloading is paused or the external constraint loading pressure is increased by one stage.

[0013] Compared with the prior art, the present invention has the following advantages and technical effects: (1) Through P c Limiting and stepped preloading provide controllable external constraint reaction forces without causing structural damage, suppressing jacking bulges caused by expansion reaction, and providing quantifiable loading boundaries for construction; (2) Using displacement δ and its rate of change as the main control variables, and grouting flow rate Q and loading pressure P as the control variables. load To coordinate the regulation amount and use the reverse pressure P back Closed-loop collaborative control involved in anomaly identification dynamically matches grouting rhythm and constraint level, improves grout diffusion path and filling uniformity, and enhances repair density and stability; (3) By using pressure-holding curing and graded unloading strategies, rebound and secondary disturbances are reduced, thereby improving repair stability and engineering repeatability. Attached Figure Description

[0014] The accompanying drawings, which form part of this application, are used to provide a further understanding of this application. The illustrative embodiments and descriptions of this application are used to explain this application and do not constitute an undue limitation of this application. In the drawings: Figure 1 This is a schematic diagram of the method flow according to an embodiment of the present invention; Figure 2 This is a schematic diagram of the loading-grouting collaborative control algorithm in an embodiment of the present invention. Detailed Implementation

[0015] It should be noted that, unless otherwise specified, the embodiments and features described in this application can be combined with each other. This application will now be described in detail with reference to the accompanying drawings and embodiments.

[0016] It should be noted that the steps shown in the flowchart in the accompanying drawings can be executed in a computer system such as a set of computer-executable instructions, and although a logical order is shown in the flowchart, in some cases the steps shown or described may be executed in a different order than that shown here.

[0017] Example 1 like Figure 1 As shown, this embodiment provides a method for the coordinated control and repair of hidden road surface defects using polymer loading grouting, including: Disease detection and classification: Non-destructive testing is performed on the pavement to be repaired to determine the type of hidden disease, obtain the disease depth h, disease thickness or opening b, planar dimension A, porosity φ, and obtain the pavement layer structure parameters; Modeling and Loading Boundary Determination: A fluid-structure interaction model was established to determine the relationship between slurry flow and diffusion and the response of the overlying pavement structure, allowing for an uplift threshold δ. allow With the allowable stress threshold σ allow As constraints, determine the upper limit pressure P corresponding to the displacement safety constraints respectively. δ Upper limit pressure P corresponding to structural strength safety constraints σ And take the critical loading pressure P c =min(P δ ,P σ The equivalent expansion pressure P of the slurry is obtained through limited expansion or constrained expansion tests. exp And determine the preload lower limit P min =k1 P exp Where k1 is 1.1 to 1.5; Preloading parameter determination and verification: Calculate the initial preloading value P0 based on the disease depth, slurry density, gravitational acceleration, expansion ratio, and correction factor, and limit it to [P]. min ,P cThe preloaded target pressure P is obtained within the [internal range]. load On-site, stepped preloading was employed with real-time displacement monitoring. Loading was stopped when the displacement reached the warning displacement threshold or the displacement growth rate exceeded the displacement growth rate threshold. The stable pressure of the final stage was used as the verified preloading pressure P. load ; Expected injection volume determined: based on the equivalent volume V of the disease. d Expansion factor K exp and volume margin coefficient K v Estimated expected injection volume V est =(V d / K exp ) K v The V est Used for initial flow setting and verification during construction, not as a criterion for termination of the capping process.

[0018] Constrained grouting and closed-loop coordinated control: under preload pressure P load Polymer grouting is performed under the action of [unspecified], with a control period Δt set, and real-time data acquisition of road surface displacement δ, displacement change rate dδ / dt, and external constraint loading pressure P. load , Loading plate back pressure P back And the grouting flow rate Q; Q is adjusted in a closed loop based on the deviation between the displacement margin and the displacement change rate, and at P load ∈[P min ,P c Within the range according to P back For P load Make corrections and set the back pressure threshold P. back,low P back,high The backpressure mutation criterion is used for anomaly identification; the expected injection volume V est Used for initial flow setting and construction process comparison and verification; when the displacement response enters the plateau period and meets the stability criterion, and it is difficult to obtain effective gain by continuing injection, the injection is stopped and the pressure holding and solidification stage is entered; if the displacement continues to grow and reaches the allowable rise threshold after the injection is stopped due to the protection mechanism, the injection is stopped and the pressure holding and observation or solidification stage is entered.

[0019] Holding pressure curing, graded unloading, and acceptance: After stopping injection, at P load Under pressure maintenance T hold Time; then, unload in stages using two or more stages and monitor the rebound amount Δδ. When Δδ exceeds the rebound threshold Δδ reb The unloading or the first-level loading pressure is paused or increased until the rebound stabilizes, and the acceptance assessment is completed based on the lifting amount, rebound amount, and load-bearing index after repair.

[0020] The following further defines the key steps: (1) Critical loading pressure P c The determination; In one embodiment, three constraint limits are used to determine the upper limit of loading. The fluid-structure interaction model can be established using numerical analysis methods known in the art, and its specific modeling method, material model, and boundary conditions can be selected according to engineering needs, which does not constitute a limitation on the method of the present invention.

[0021] 1) Displacement constraint: Let the allowable lifting threshold be δ allow The displacement of key road surface points calculated by the fluid-structure interaction model reaches δ allow The corresponding loading pressure is defined as P. δ ; 2) Strength constraint: Set the allowable stress threshold σ allow The equivalent stress at key components calculated using the fluid-structure interaction model reaches σ. allow The corresponding loading pressure is defined as P. σ ; 3) Anti-jacking and lower limit constraint: The equivalent expansion pressure P of the slurry is obtained through expansion-limiting or constraint expansion tests. exp Based on this, the lower limit P of preloading is determined. min =k1 P exp .

[0022] Taking the critical loading pressure P as a comprehensive measure c =min(P δ ,P σ ), and during construction, P load ∈[P min ,P c [] serves as the loading control area.

[0023] (2) Determination of preloading parameters and on-site verification; Preloading is used to generate external constraint reaction forces before grouting and to check the deformation response of the diseased area.

[0024] In one implementation, the initial preload value is first calculated using an empirical formula: P0 = rho slurry g h K exp γ, where γ is a correction coefficient, preferably 0.6 to 1.2; and P0 is limited to [P min ,P c Within [the specified range], the preloaded target pressure P is obtained. load .

[0025] A stepped loading method was adopted on site: the increment of each loading step could be 0.1–0.2 MPa or 0.1–0.25 MPa. load Maintain t at each level p (Preferably 0.5 to 2 min) to observe displacement stability.

[0026] The pressurization will stop when either of the following conditions is met: a) The displacement reaches α δ allow α is preferably 0.6 to 0.8, and a smaller value is taken when the structure is fragile, cracks are developed, or it is near a sensitive target; b) The displacement-pressure response shows obvious nonlinear abrupt change.

[0027] After the pressurization stops, the stable pressure value of the last stage is used as the preload pressure P after verification. load During the subsequent grouting stage, the external constraint pressure is maintained at P. load .

[0028] (3) Estimation of expected injection volume and setting of differentiated parameters; The expected injection volume is used for setting the initial grouting flow rate and verifying it against the construction process, and is used together with displacement and back pressure response for process decision-making; differentiated parameters are used to adapt to the filling, compaction and jacking risk control of different types of defects.

[0029] Equivalent volume of disease V d Determination: For voids or cavities, V can be estimated based on the detected planar dimension A and the average void thickness b. d ≈A b; For crack defects, V can be estimated based on crack length L, average aperture b, and effective diffusion thickness t. d ≈L b For loose soil defects, V can be estimated based on the planar dimensions A of the loose area, the thickness b of the loose soil, and the porosity φ. d ≈A b φ. V d It can also be corrected by combining core drilling, test injection back calculation, or multi-source inversion.

[0030] Expected injection volume V est Determination: Based on the slurry expansion ratio K exp and volume margin coefficient K v Estimate V est =(V d / K exp ) K v K vThe preferred value is 1.0 to 1.3, which is used to compensate for non-uniform porosity, loss and measurement error; the Vest is used for initial flow setting and comparison with the construction process, and is not used as a criterion for capping termination.

[0031] Differentiated parameter settings: For different disease types such as cracks, voids, and loosening, rate-limiting coefficients β and process strategies are set. For cracks, the focus is on controlling jacking and preventing crack propagation, with β preferably between 0.5 and 0.8, and segmented low-flow injection is recommended. For voids, the focus is on filling, with β preferably between 0.7 and 1.0, and multi-point zonal injection and borehole rotation are recommended. For loosening, the focus is on low-pressure infiltration and compaction consolidation, with β preferably between 0.6 and 0.8, and low-flow multiple injections, borehole rotation, and intermittent grouting are recommended; the holding time T should also be appropriately extended. hold (Preferably 15-30 min), while appropriately extending the interval time to promote curing and molding.

[0032] (4) Constrained grouting and closed-loop coordinated control; In one embodiment, the loading plate counter-pressures P back The load on the road surface fluctuates due to changes in the contact state of the loading plate, the nonlinear response of the road structure, and the fluctuations in the loading system loop, making it difficult to use as a continuous and stable control target. Therefore, this invention adopts the control concept of "displacement as the main control, coordinated adjustment of grouting volume and loading pressure, and back pressure participation in the judgment": the road surface displacement δ and its rate of change r(t) = dδ / dt are the main control variables, and the grouting flow rate Q and the external constraint loading pressure P are the control variables. load As a coordinated regulating quantity, and with P back Used for constraint effectiveness assessment, anomaly identification, and P. load Correction. The loading-grouting coordinated control algorithm flow is as follows: Figure 2 As shown.

[0033] Initialization and parameter setting: Maintain the external constraint loading pressure at P. load Establish a displacement baseline δ(t0) = 0; set an allowable lifting threshold δ allow Early warning displacement threshold δ w (δ) w <δ allow ), where δ w Preferred according to δ w =δ allow -Δδ lag -Δδ noise Determined, Δδ lag For the hysteresis displacement after load or injection stoppage, Δδ noise To provide noise margin for displacement monitoring; set an upper limit threshold r for the rate of change of displacement. lim Warning change rate threshold r pre (r) pre =ν rlim (ν is preferably 0.7 to 0.9) and the displacement change rate control target r set (satisfying r) set ≤μ r pre (μ is preferably 0.5 to 0.8); set the expected injection volume V. est Used for initial flow setting and process comparison; sets the baseline grouting flow rate Q0; flow command Q. cmd Performed by pump / valve and limited to the range that the equipment can operate within [Q] dev,min ~Q dev,max Set the back pressure threshold P. back,low P back,high and the back pressure mutation threshold ΔP back,drop Used for anomaly detection; sets the loading pressure boundary P. load ∈[P min ,P c ].

[0034] Cyclic data acquisition and characteristic quantity calculation: Data acquisition and calculation are performed cyclically during the grouting stage, with the control cycle Δt preferably being 1–5 seconds; δ(t) and P are acquired in real time. back(t) P load(t) Q(t) can be used to determine δ(t) and P. back(t) Perform sliding window filtering; calculate the displacement change rate r(t) = dδ / dt and the monitoring window displacement increment Δδ based on the acquired signal. win , back pressure change ΔP back And calculate the cumulative injection amount V(t)=∫Q(t)dt.

[0035] Closed-loop control output (normal closed loop): Under conditions where no protection or abnormality is triggered, the output is controlled by a displacement margin (δ). w −δ) and the deviation of the rate of change (r) set Based on the baseline flow rate Q0 or the feedforward flow rate Q, −r(t)) is used to determine the baseline flow rate Q0 or the feedforward flow rate Q. ff(t) The correction is performed to generate and limit the baseline flow command Q. base(t) And by default, the external constraint loading pressure P is maintained. load =P load When the displacement margin decreases or the displacement change rate increases, the flow rate command automatically tends to decrease to suppress displacement development; when the displacement margin is sufficient and the displacement change rate is lower than the target level, it is allowed to maintain or moderately increase the flow rate to improve filling efficiency; Q is generated. base(t) Then, it enters S604 for judgment; if it is not triggered, it outputs Q. cmd(t) =Q base(t) Then return to loop S602.

[0036] Protection or abnormal triggering discrimination (backpressure involved in discrimination): after obtaining Q base(t)Then, based on δ(t), r(t) and P back(t) Perform a judgment; if no protection / abnormality is triggered, then execute Q. cmd(t) =Q base(t) Then return to S602 to continue the loop; if a protection / abnormality or stop condition is triggered, proceed to S605 for handling, and after handling, press S606 to perform termination judgment and stage switching.

[0037] 1) Early warning and reduction (priority handling): When δ(t)≥δw or r(t)≥r pre At that time, Q cmd From Q base The data was downgraded to a conservative range and placed under reduced monitoring, for example, Q. cmd =max(Q dev,min ,λ down Q base ), λ down The preferred value is 0.3 to 0.7; r(t) is continuously calculated during the reduction monitoring period. If r(t) is still ≥ r after N consecutive confirmations, pre If this is triggered, the system will stop and enter S605 observation hold mode to avoid displacement overshoot caused by injection delay.

[0038] 2) Constraint effectiveness decreases: when P back(t) ≤P back,low , or ΔP back When a sudden drop occurs accompanied by abnormal displacement response, an abnormality handling mechanism is triggered and the process enters S605. In S605, injection is paused and the contact status of the loading plate is checked. If necessary, P is adjusted within the limit of Pc. load In [P] min ,P c The internal force is moderately increased to rebuild the constraint reaction force.

[0039] 3) Diffusion is hindered / approaching saturation: When P back Continued rise approaching or reaching P back,high , or ΔP back ≥ΔP back,drop And Δδ win <5 res δ When the situation becomes apparent, an anomaly is triggered and the system enters S605. In S605, Q is down-adjusted and the system is switched to observation hold or intermittent injection to promote diffusion and reduce the risk of local overpressure.

[0040] 4) Lift Sensitivity: When the road surface displacement reaches the lift sensitivity displacement threshold, or the displacement change rate reaches the lift sensitivity change rate threshold (i.e., δ approaches δ...) w Or r(t) is close to r lim And P back <Back pressure ineffective threshold (5) res pWhen this occurs, exception handling is triggered and the process enters S605; in S605, Q is preferentially reduced and r is tightened. set And in P load Not reached P c Under the premise that P can be load In [P] min ,P c The internal adjustment is moderately increased to enhance the anti-top constraint. The sensitive displacement threshold for jacking is less than the warning displacement threshold δ. w The displacement value is used to identify sensitive conditions near the warning zone of jacking risk; its value can be determined based on δ. w Determine by multiplying by a coefficient less than 1 (e.g., 0.8~0.95); the threshold for the rate of change of jacking sensitivity is less than r. lim The rate of change is used to identify sensitive states where the jacking rate is near the warning zone; its value can be determined based on r. lim Determine by multiplying by a coefficient less than 1 (such as 0.8~0.95).

[0041] Action taken: Based on the S604 judgment result, take action, including dose reduction monitoring, observation maintenance, intermittent injection, and pressure adjustment. Observation maintenance involves stopping injection and continuously monitoring δ(t), r(t), and P. back(t) During this period, it is preferable to maintain P. load =P load During intermittent injection, an observation hold time (T) can be set. stop (Preferred time: 10-120s), Injection duration T on (Preferred 5-30s) and intermittent holding T off (Preferably 10-60s), and a reduction factor λdown (preferably 0.3-0.7) can be used to proportionally reduce the flow rate; when the effectiveness of the constraint is determined to decrease, [P] min ,P c Internal adjustment of P load To reconstruct the constraint reaction force, P can be moderately increased within a safe range when the lifting sensitivity is determined. load To enhance the anti-top constraint.

[0042] Termination Criteria and Stage Switching: In each loop, a termination criterion is used for judgment. Firstly, plateau termination: When the displacement response enters a plateau period and meets the stability criterion, injection stops and the system enters the pressure-holding solidification stage. The stability criterion is the value of Δδ within the continuous monitoring time window. win ≤ε δ Secondly, protection termination: When S605 has triggered a stop and entered observation hold, if the displacement continues to increase after the injection stops and reaches δ... allow If the pressure remains unchanged, the observation / curing phase will begin; if δ(t) falls back to a safe range (e.g., δ(t) < δ), the pressure will be maintained and the system will enter the observation / curing phase. w And r(t)≤r set And Pback,low <P back <P back,high If the initial flow rate is conservative, injection can be resumed and the cycle can return to S602 to continue. Whether to resume injection is determined based on the results of the on-site safety assessment; resuming injection is not a mandatory step. Expected injection volume V est The cumulative injection amount V(t) is used for process comparison and traceability, but not as a criterion for capping and termination.

[0043] (5) Holding pressure curing and staged unloading; Pressure holding and solidification criteria: After grouting is completed, the pressure holding and solidification stage begins, maintaining the external constraint pressure at P. load To suppress springback and promote curing. Holding time T hold Not less than the initial setting time of the slurry t set The displacement increment is 1.0 to 2.0 times that of the threshold ε, and meets the displacement stability criterion: the displacement increment is less than the threshold ε within the continuous monitoring time window. δ The preferred monitoring time window is 2–10 minutes, ε δ The optimal value ε can be determined by combining displacement monitoring noise and allowable rise threshold. δ =max(κ σ δ η δ allow ), σ δ The standard deviation of the displacement sequence during the initial stable phase of pressure holding is given by κ, which is preferably 2 to 3, and η is preferably 0.02 to 0.05.

[0044] Abnormal handling and replenishment criteria during the holding phase: If the displacement continues to increase or the stability criterion is not met during the holding period, the holding time shall be extended and continuous monitoring shall be maintained; replenishment shall be required when any of the following situations occur: a) Under the condition that the initial setting time has been met, the displacement still shows a monotonic decline and the decline exceeds ε δ b) Short-term unloading or deloading tests show that the rebound amount is close to or exceeds the rebound threshold Δδ reb .

[0045] Staged unloading start-up: After the holding time and stability criteria are met, staged unloading is started, and the external constraint pressure is reduced step by step according to the grade difference; the grade difference can be a fixed value or a proportional decrease.

[0046] Retention and rebound monitoring at each unloading stage: Retention time is maintained after each unloading stage is completed. u (Preferred time: 2-10 min) Monitor displacement rebound amount Δδ.

[0047] Rebound threshold triggering and backoff control: If Δδ exceeds the rebound threshold Δδ reb ,Δδ reb =max(κ2 σδ , ζ δ allow If κ is preferably 2-3 and η is preferably 0.1-0.3, then the unloading is paused or the external constraint pressure is increased by one level and maintained again until the rebound tends to stabilize; when several consecutive levels satisfy Δδ≤Δδ reb Continue uninstalling until the process is complete.

[0048] Unloading completion and acceptance evaluation: After unloading is completed, record the final displacement, residual deformation and stability, and evaluate them in conjunction with the on-site acceptance indicators; if abnormal rebound or unstable trend occurs, extend the holding pressure or adjust the unloading level difference and holding time according to the above five steps.

[0049] The symbols and their meanings in the above content are shown in the table below: Table 1 Example 1 (Crack Defect): A semi-rigid base asphalt pavement of a highway exhibited water seepage and localized subsidence near the joints. 3D ground-penetrating radar detection, combined with borehole verification, identified it as a crack-type hidden defect. The crack length was approximately 8 m, the average aperture was approximately 3 mm, the effective diffusion thickness was approximately 0.30 m, and the defect depth was approximately 0.30 m. Based on this, the equivalent volume of the defect was estimated to be approximately 7 L. According to the road grade and smoothness control requirements, the allowable lift threshold δ... allow Take 2.0 mm.

[0050] For this type of pavement defect, a fluid-structure interaction model of the grout and overlying pavement was established to analyze the relationship between external loading pressure, pavement displacement, and stress at key locations. The model calculations showed that when the displacement at key pavement points reaches the allowable uplift threshold δ... allow At that time, the corresponding loading pressure P δ Approximately 0.70 MPa; when the equivalent stress in critical components reaches the allowable stress threshold σ allow At that time, the corresponding loading pressure P σ The critical loading pressure P is approximately 0.60 MPa. c It is approximately 0.60 MPa.

[0051] The equivalent expansion pressure P of the expansion slurry used was measured by the expansion-limiting test. exp Approximately 0.25 MPa, with a safety factor k1 = 1.2, determine the lower limit of preload P. min It is approximately 0.30 MPa. The P... c With P minAs a loading control boundary, it is used to guide the on-site loading and grouting process. Its value can be checked and corrected through subsequent stepped loading and displacement monitoring.

[0052] Preload pressure was applied on-site using a stepped loading method, at [P] min P c The load was gradually increased within the interval, with each increment ranging from 0.05 to 0.10 MPa, and each increment was maintained for approximately 1 minute, while the road surface displacement response was monitored in real time. Once the displacement response stabilized, the final calibrated preload pressure P was determined. load The pressure is approximately 0.45 MPa. During the preload holding phase, the displacement noise level and displacement change rate are statistically analyzed, and a warning displacement threshold δ is set. w Displacement change rate threshold r lim With r pre and control target r set Simultaneously, the back pressure threshold P is determined based on the steady-state level and fluctuation range of the back pressure of the loading plate. back,low With P back,high .

[0053] The grouting stage is implemented using a segmented, low-flow injection method. The grout expansion ratio K is taken. exp =8. Volume margin coefficient K v =1.1, estimated expected injection volume V est The initial grouting flow rate Q0 is set to approximately 1.0 L, preferably 0.05–0.20 L / min. Polymer grouting is performed under preload constraints, and the pavement displacement δ, displacement change rate r(t), and loading plate back pressure P are collected in real time. back Based on the monitoring status, the grouting flow rate and loading pressure are coordinated and adjusted within the loading control range: when the displacement or its rate of change approaches the warning threshold, the grouting intensity is reduced; when the back pressure change indicates that the constraint effectiveness has decreased or diffusion is blocked, the system is switched to observation maintenance or intermittent injection to improve the grout diffusion state.

[0054] Once the pavement displacement reaches the target value and the displacement change meets the stability criterion, the injection process stops, and the process enters the pressure-holding and curing stage. Subsequently, a staged unloading method is used to release external constraints and monitor rebound. Construction results show that the maximum uplift is approximately 1.1 mm, which is less than the allowable uplift threshold, the unloading rebound is less than 0.3 mm, the water seepage phenomenon is significantly alleviated, and the overall stability of the repaired pavement is improved.

[0055] Example 2 (Voiding disease): A semi-rigid base asphalt pavement on a highway experienced subsidence at the slab ends and joint areas, accompanied by pumping. Ground-penetrating radar (GPR) detection identified a void area on the top surface of the base layer, approximately 1.5 m × 1.2 m in size, with an average void thickness of about 25 mm and a depth of about 0.35 m. Based on this, the estimated equivalent volume of the damage is approximately 45 L. According to engineering control requirements, the allowable uplift threshold δ... allow Take 1.2 mm.

[0056] For this type of road defect, a fluid-structure interaction model of the slurry-overlay pavement was established to analyze the relationship between the loading pressure, pavement displacement, and stress in key areas. The model calculated the displacement constraint pressure P. δ Approximately 0.55 MPa, strength constraint pressure P σ The critical loading pressure P is approximately 0.65 MPa. c It is approximately 0.55 MPa.

[0057] The equivalent expansion pressure P of the slurry was measured by the expansion-limiting test. exp Approximately 0.20 MPa, take k1=1.3, and determine the lower limit P of preloading. min The pressure was approximately 0.26 MPa. On-site construction employed a four-hole zoned layout. The stepped preload was increased from 0.26 MPa to 0.50 MPa and maintained for approximately 2 minutes. The displacement response tended to stabilize, and the verified preload pressure P was determined. load The pressure is approximately 0.50 MPa. Simultaneously, during the preload holding phase, displacement noise and hysteresis margin are statistically analyzed, and δ is set. w r lim r pre With r set And determine P based on the counter-pressure steady-state level. back,low P back,high and the back pressure mutation threshold ΔP back,drop .

[0058] Take the slurry expansion ratio K exp =10, Volume margin coefficient K v =1.2, estimated expected injection volume V est The reference grouting flow rate Q0 is set to approximately 5.4 L, preferably 0.3–0.8 L / min. Grouting is implemented using a "zonal rotation + intermittent injection" method. During grouting, the grouting flow rate is adjusted in a closed loop based on the displacement margin and the deviation of the rate of change. When the displacement approaches the warning threshold, the grouting intensity is reduced and continuous monitoring is maintained. When the back pressure continues to increase and the displacement increment is not significant (when P...), the grouting flow rate is adjusted accordingly. back Continued rise approaching or reaching P back,high , or ΔP back ≥ΔP back,drop And Δδwin <5 res δ ), switch to observation and maintenance or intermittent injection; when the back pressure drops abnormally, grouting is suspended and the contact status of the loading plate is checked. If necessary, the loading pressure is corrected without exceeding Pc.

[0059] After the repair was completed, radar retesting showed that the delamination range had disappeared, the maximum lift was about 1.0 mm, the unloading rebound was about 0.3 mm, and the driving vibration and mud pumping phenomenon were eliminated.

[0060] Example 3 (Looseness disease): Localized network cracking and increased deflection were observed in the semi-rigid base asphalt pavement of a highway. Comprehensive testing using ground-penetrating radar and a falling-weight deflectometer determined it to be a hidden defect caused by a loose base layer. The loose area has planar dimensions of approximately 2.0 m × 1.8 m, a thickness of approximately 40 mm, and a porosity of approximately 0.40. Based on this, the estimated equivalent volume of the defect is approximately 60 L. According to engineering control requirements, the allowable uplift threshold δ... allow Take 1.0 mm.

[0061] For this specific fault condition, a fluid-structure interaction model of the slurry and solid was established, and the displacement constraint pressure P was calculated. δ Approximately 0.40 MPa, strength constraint pressure P σ The pressure is approximately 0.48 MPa; therefore, the critical loading pressure Pc is taken as approximately 0.40 MPa. The equivalent expansion pressure P of the slurry was measured by the expansion-limiting test. exp Approximately 0.18 MPa, take k1=1.2, and determine the lower limit P of preloading. min It is approximately 0.22 MPa.

[0062] On-site, a stepped preloading method was used to increase the load to 0.35 MPa. The displacement response tended to stabilize, and the verified preloading pressure P was determined. load The pressure is approximately 0.35 MPa, and δw, rlim, rpre, rset and the back pressure threshold are set based on the statistical results of the preload holding section.

[0063] For loose-type defects, the remediation target is mainly low-pressure infiltration and compaction consolidation. The slurry expansion ratio Kexp = 8 and the volume margin coefficient K are used. v =1.3, estimated expected injection volume V est Approximately 9.8 L was injected using a low-flow-rate, multiple-injection method with alternating borehole positions. The preferred grouting flow rate Q0 was 0.2–0.6 L / min, with relatively long intervals maintained to promote grout penetration and solidification. During grouting, pavement displacement and its rate of change were the primary control parameters, and the counter-pressure of the loading plate was used to determine the effectiveness of the constraint and the diffusion state. If necessary, [P]min P c The loading pressure is adjusted within the specified range.

[0064] After the repair was completed, the deflection index was significantly improved, the pressure holding and curing time was extended to 25-30 minutes, the rebound during the graded unloading process met the threshold requirements, and no significant re-sinking was observed in subsequent inspections.

[0065] This invention can be used for the repair of hidden defects in municipal roads, highways, airport pavements, etc. It can be integrated with existing grouting equipment, loading devices and conventional detection sensors, and has good engineering feasibility and promotion value.

[0066] The above are merely preferred embodiments of this application, but the scope of protection of this application is not limited thereto. Any variations or substitutions that can be easily conceived by those skilled in the art within the scope of the technology disclosed in this application should be included within the scope of protection of this application. Therefore, the scope of protection of this application should be determined by the scope of the claims.

Claims

1. A method for repairing road surface hidden diseases by polymer loading and grouting, characterized in that, Includes the following steps: Non-destructive testing is used to obtain the type of pavement defects, geometric parameters of defects, and pavement layer structure parameters of the road surface to be repaired. A fluid-structure interaction model is constructed based on the geometric parameters of the disease and the layered structure parameters of the pavement; the critical loading pressure is determined based on the fluid-structure interaction model, and the lower limit of preloading is determined by combining the slurry equivalent expansion pressure test; The initial preload value is calculated based on the geometric parameters of the defect; the initial preload value is limited between the lower limit of the preload and the critical loading pressure to obtain the target preload pressure; based on the target preload pressure, the preload pressure is checked by step preload and monitoring of road surface displacement to obtain the checked preload pressure; The estimated injection volume is estimated based on the equivalent volume of the defect, the slurry expansion ratio, and the volume margin coefficient. Polymer grouting was carried out under the preloaded pressure constraint after verification, and the initial grouting flow rate was set according to the expected injection volume. The control target is the road surface displacement and the corresponding rate of change. The grouting flow rate and the external constraint loading pressure are adjusted in a coordinated manner, and anomalies are identified and corrected based on the back pressure of the loading plate. The injection is stopped when the preset conditions are met. After stopping the injection, perform pressure maintenance, graded unloading and rebound monitoring in sequence, and complete the acceptance based on the condition after unloading.

2. The method for coordinated control and repair of hidden road surface defects by polymer loading grouting according to claim 1, characterized in that, The non-destructive testing includes using three-dimensional ground-penetrating radar and a falling-weight deflectometer, combined with drilling or core sampling to verify the geometric parameters of the defects.

3. The method for coordinated control and repair of hidden road surface defects by polymer loading grouting according to claim 1, characterized in that, The process of determining the critical loading pressure based on the fluid-structure interaction model includes: using the fluid-structure interaction model, calculating the displacement constraint pressure corresponding to when the road surface displacement reaches the allowable uplift threshold, and the strength constraint pressure corresponding to when the equivalent stress of the key parts of the road surface reaches the allowable stress threshold, and taking the smaller value of the two as the critical loading pressure.

4. The method according to claim 1, wherein the method is characterized by, The lower limit of preloading is equal to the equivalent expansion pressure of the slurry measured by the limited expansion or constrained expansion test multiplied by a safety factor of 1.1 to 1.

5.

5. The method for coordinated control and repair of hidden road surface defects by polymer loading grouting according to claim 1, characterized in that, The process of verification through stepped preloading and monitoring road surface displacement includes: External constraint loading pressure is applied at each loading increment of 0.1 to 0.2 MPa or 0.1 to 0.25 times the preload target pressure, and maintained for 0.5 to 2 minutes after each loading increment; when the monitored road surface displacement reaches the warning displacement threshold or its rate of change exceeds the displacement growth rate threshold, the pressure increase is stopped and the current stable pressure is used as the verified preload pressure.

6. The method of claim 1, wherein the method further comprises: applying a polymer to the surface of the road to form a polymer layer; and applying a polymer layer to the surface of the road to form a polymer layer. The process of estimating the expected injection volume based on the equivalent volume of the defect, the grout expansion ratio, and the volume margin coefficient includes: The expected injection volume is equal to the equivalent volume of the disease divided by the slurry expansion factor, and then multiplied by a volume margin coefficient of 1.0 to 1.3; wherein, the equivalent volume of the disease is determined according to the disease type based on the planar dimensions and thickness, crack dimensions or loose zone dimensions and porosity.

7. The method for coordinated control and repair of hidden road surface defects by polymer loading grouting according to claim 1, characterized in that, The process of using road surface displacement and its corresponding rate of change as control targets, coordinating the adjustment of grouting flow rate and external constraint loading pressure, and identifying and correcting anomalies based on the back pressure of the loading plate includes: Set the following thresholds: early warning displacement threshold, displacement change rate threshold, jacking sensitive displacement threshold, jacking sensitive change rate threshold, low back pressure threshold, high back pressure threshold, back pressure sudden change threshold, and back pressure invalid threshold; wherein, the jacking sensitive displacement threshold is less than the early warning displacement threshold, and the jacking sensitive change rate threshold is less than the displacement change rate threshold; When the back pressure of the loading plate is lower than the low value of the back pressure threshold, grouting is paused and the contact state of the loading plate is checked. Based on the check result, the external constraint loading pressure is increased within the range of the preload lower limit and the critical loading pressure. When the back pressure of the loading plate is higher than the high value of the back pressure threshold or the back pressure increment exceeds the back pressure sudden change threshold, reduce the grouting flow rate and switch to intermittent grouting or observation and maintenance. When the road surface displacement reaches the warning displacement threshold or the displacement change rate reaches the displacement change rate threshold, the grouting flow rate is reduced and the grouting is monitored for volume reduction. If the displacement change rate continues to exceed the displacement change rate threshold during the volume reduction monitoring period, grouting is stopped and the monitoring is switched to observation and maintenance. When the road surface displacement reaches the lifting sensitive displacement threshold or the displacement change rate reaches the lifting sensitive change rate threshold, and the back pressure of the loading plate is lower than the back pressure ineffective threshold, the grouting flow rate is reduced and the displacement change rate control target is tightened. At the same time, the external constraint loading pressure is increased without exceeding the critical loading pressure.

8. The method according to claim 1, wherein the method is characterized by, The process of setting the initial grouting flow rate also includes setting differentiated rate limiting coefficients for different types of defects and adapting them to different grouting processes, including: When the disease type is crack, a rate limiting coefficient of 0.5 to 0.8 is used, and a segmented small flow injection process is adopted; When the disease type is voiding, a rate limiting coefficient of 0.7 to 1.0 is used, and a multi-point zonal injection or hole position rotation injection process is adopted. When the disease type is loose, a rate limiting coefficient of 0.6 to 0.8 is used, and a process of alternating hole positions and intermittent injection is adopted.

9. The method according to claim 1, wherein the method is characterized by, The duration of the pressure-holding curing is not less than 1.0 to 2.0 times the initial setting time of the slurry; during the staged unloading process, each stage of unloading is maintained for 2 to 10 minutes. If the detected rebound amount exceeds the rebound threshold, the unloading is suspended or the external constraint loading pressure is increased by one stage.

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